The present invention relates to explosive assembly systems suitable to couple different explosive components together in a field setting and related methods. In particular, one exemplary explosive assembly system can include an initiator structure that improves initiation and detonation of a linear shaped charge (LSC). For example, end priming of LSCs can be made more efficient, reliable, safer, and simpler over existing approaches, e.g., hand taped methods. Some embodiments of this disclosure can include an initiation apparatus configured to engage with a “V” cross section of LSCs so can be referred to herein as a “V-Prime”. While one example of the present invention can include one or more exemplar V-Prime designs, fitted to 4000 gr/ft CLSC, LSCs come in many cross-sections of explosive load. An exemplary V-Prime design can be adapted to receive various explosives or LSC designs and shapes. A V-Prime as discussed with regard to at least some embodiments of the invention can include a body, e.g., a rubber end cap, with a hollow neck designed to fit snuggly onto an end of a piece of LSC and provide a structure for assembling or attaching and retaining a detonator cord with a variety of new advantages and capabilities.
Various approaches in existence have substantial disadvantages. For example, use of tape to assemble LSC pieces including taping an explosive sheet booster and a detonator together can be done in a field setting. However this approach has numerous disadvantages such as unreliability, etc.
Recent improvements in response time and availability of capabilities for rapid prototyping materials have raised a possibility and practicality of introducing custom components that increase the efficiency, reliability, safety, and simplicity of the detonation. For example, one embodiment of a V-Prime improves assembly and use of LSCs in a variety of ways. First, an exemplary V-Prime makes LSC easier to use by adding a manufactured structure to the end of the charge that simplifies priming the charge. Priming the charge involves accurately placing a detonator, detonation cord (detcord), or other initiating device. Priming was traditionally done by wrapping tape around the detonator, LSC, and explosive sheet booster, if required. Adding a manufactured structure however, simplifies priming, thus making the LSC easier to use. Second, the V-Prime makes the LSC more reliable by placing explosive sheet booster material in secure, direct contact with the explosive core of the LSC. Previously, the explosive sheet booster material was either taped on top of the charge, or across the end of the LSC, and then a detonator was placed and taped into or on the explosive sheet booster. Taping explosive sheet booster material on top of the LSC required either filing or removing parts of the LSC metal wall. Filing the LSC metal jacket, or removing parts of the LSC metal wall by other means to reach the explosive core for a reliable initiation could be very dangerous. Additionally the explosive sheet booster material was in parallel to the LSC, which decreased the performance of the detonator. Taping explosive sheet booster material across the end involved placing material along a small cross-section, which is less secure, and 90° from the optimal direction to pass the shock front from the explosive sheet booster to the LSC. Therefore, the V-Prime provides a major improvement in securing the contact between the explosive sheet booster material and the explosive core by providing internal cavities that securely house the necessary components (explosive sheet booster, detcord, LSC). In addition, the V-Prime makes the LSC more reliable. Third, the V-Prime makes the LSC safer by protecting the explosive ends of the LSC from impacts and drops. The V-Prime provides a rubber “bumper” to protect the exposed explosive ends of the LSC. Protecting the exposed ends improves the safety of the overall device. Fourth, the V-Prime improves the performance of the LSC. LSCs typically take up to three inches of their length to run-up, or detonate to optimal performance. End priming the LSC with the V-Prime device gives the charge added momentum by reducing the typical run-up distance. Also, because the V-Prime is placed on the end of the charge, and not placed across the top of the charge, the LSC is not over primed. Over priming occurs when a top mounted explosive sheet booster disrupts the effect of the LSC, and further increases the necessary run-up.
Additionally, the explosive sheet booster loaded exemplary V-Primes can be transported on the LSC to the point of operation because the explosive sheet booster materials in the V-Prime are of the same hazard class as the LSC. Therefore, in an exemplary embodiment of the device, when on target, the user inserts a detonator into the neck of the V-Prime and initiates the charge with a detonator from a safe distance.
According to an illustrative embodiment of the present disclosure, some features of one embodiment, e.g., an explosive assembly or LSC End Prime Cap, can include: (1) In-line priming where the priming can be optimally done on the same axis that the LSC will detonate on. This improves the performance of the LSC. (2) Secure explosive sheet booster attachment where the inside of the V-Prime can be sized to fit explosive sheet, flexible boosters, explosive sheet boosters or all types of boosters. Without an embodiment, e.g., the V-Prime, a user is required to use undesirable field assembly approaches such as taping explosive booster material to a side of the LSC, thus creating an unsecured explosive sheet booster attachment. (3) An incorporation of another structure, a U-Prime including a well structure, where the U-Prime allows for quick, versatile and secure insertion of the detonator. Various embodiments of an exemplary V-Prime can be designed to fit other sizes of LSC. Additionally, there may be other demolition related uses for charges other than LSC that benefit from a rubber end priming sleeve predominantly of these features.
Generally, embodiments of the invention can include a coupling or assembly structure adapted for holding various components including an initiator structure adapted to initiate an explosive sheet booster explosive material, the explosive sheet booster material, and the LSC in abutting contact with each other. One embodiment includes an elastomeric or rubber body formed with cavities adapted to receive the LSC, explosive sheet booster, and initiator structure (e.g., detonation cord). One internal cavity can be formed with a plurality of flexible protrusions or fins which are oriented towards a center axis of the three cavities configured to impart an interference fit with the initiator structure or detonator cord. Methods of use are also provided.
Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived.